In 2012, the federal government classified koalas as “vulnerable”in the states of New South Wales, Queensland and Australian Capital Territory. The Australia Zoo estimates there are 40,000 to 100,000 koalas — a symbol of Australia’s unique wildlife — remaining in the wild.

So how is the disease transmitted?

The usual way — so stop visualizing it! Though transmitted through sex, koalas have little time for randy rooting, as the Australians call it, because they sleep about 20 hours a day.

There are two main strains of bacteria that lead to chlamydia in the marsupials. The more common strain, Chlamydia pecorum, is responsible for most of the outbreak in Queensland and cannot be transmitted to humans.

The second strain, C. pneumoniae, can infect humans if, say, an infected koala were to urinate on someone, though it’s unlikely. (Try sharing that tidbit next time a friend sends you a cute koala pic.)

Baby koalas, known as joeys, can also catch the disease from their mothers while nursing if they come into contact with infected feces.

Is there a cure?

For humans, treatment of the disease involves an embarrassing trip to the doctor for antibiotics (and maybe a few angry texts).

Antibiotics are also used to treat koalas, although they do not prevent re-infection and come with a host of unpleasant side effects. Research has shown that the treatment messes with the gut microbes that help them digest their leafy diet — meaning they can starve.

There have been successful trials of a vaccine to prevent infection in both healthy koalas and those in early stages of infection. Some of those experiments have taken place at the very wildlife hospital where Mr. Oliver’s name now adorns the wall.

And don’t worry, the Australian government isn’t letting Mr. Oliver have all the credit: Just this Monday, the New South Wales government announced a 45 million Australian dollar plan to save the state’s koalas. (That’s almost $34 million.)

What did John Oliver actually get?

Apart from his name forever memorialized with the words “koala chlamydia,” a ward in Mr. Oliver’s honor was donated at the Australia Zoo Wildlife Hospital in Queensland. The ward will focus on treating and vaccinating koalas in that state.

“Thanks to your auction, you are now saving literally thousands of koala lives,” said Bindi Irwin, daughter of the conservationist Steve Irwin, who died in 2006, in a video tweeted out by Mr. Crowe.

The reward was all too much for Mr. Oliver, who joked Sunday on his show, “Last Week Tonight With John Oliver,” that he was so overcome by the accomplishment that he was done hosting it.

“Don’t think of this as a sad occasion, because I leave you in total triumph at this point,” he said. “If you’ll excuse me, I’ve got a date with some very contagious koalas.”